Tap chuck with overload coupling



Sept. 26, 1950 R. J. MILLER 2,523,584

TAFCHUCK WITH OVERLOAD COUPLING Filed may 1s, 1949 In ventor Rqymond J. Miller 2mm WWW, 29%

Patentecl Sept. 26, 1950 UNITED STATES PATENT OFFICE 'rAPcnUoK-wrrn-ovmnmm GOUPEING- Raymond-L riflorr i a. epnlicat nMax' 1s, ,;Spr a iNn- 3.9 .1-

1 a Y r The present invention relates to a tap-holding; and drivingchu ck which has incorporated therein a safety-type overload coupling, a portion-or said coupling also functioningas a taper-shankwhich is driven by a suitable; sourceof power.

The obviousobject-and purpose of theinvention is to automatically uncouplethe tap from thechuck, or vice versa,'soas to automatically-mm. tect the respective parts from breakage whenan excessive or abnormalload is imposed on the stated chuck.

More particularly, novelty predicated upona spring-pressed overrunning clutch functioning as the automatic coupling, said clutch providing the new feature of the chuck.

Briefly described; the clutch is characterized bye'a socket. member threaded" into one end of a complemental spring casing, said, socketmemberhaving an axial extension projectingtelescopically into an axial recess in one end portion of the taper-shank, a coiled spring in the casing surrounding the coacting end portionof the tapershank, thelatter-beingflanged: to provide one of the accompanying members; said} coupling-memberbeing opposed to the socket member-and the two having ball seats-or depressions therein to accommodate the motion-transmitting balls.

No doubt, the artto which the invention relates is characterized by pipe and rod couplings and the idea of incorporating therein an overrunning clutch is perhaps not new. It is believed that by utilizing one end of a socket member as one coupling element, the flange on a taper-shank as the opposed coupling element, and balls between the two elements wherein all parts are of simplified construction and arrangement constitutesa nove1 so-called tap-holding and driving chuck.

Other objects, features and advantages will become more readily apparent from the following description and the accompanying drawings.

In the sheet of drawings, wherein like numerals are employed to designate like parts throughout the several figures: I

Figure l is an elevational view of a tap-accommodating and holding chuck constructed in accordance with the principles of the present invention.

Figure 2 is a view upon a slightly enlarged scale showing the details which gov to make up the chuck with the safety coupling feature.

Figure 3 is a cross-section on the horizontal line 3-3 of Figure 2, looking in the direction 'of the indicating arrows.

Referringnow to the drawings by reference onal portion corresponding with and adapted to fitintoa correspondingly shaped socket l in-the socket member 8. The socket member 8, which constitutes one of the essential'unitsof the overall chuck; is denotedina unitary Wayby the: numeral 9; Oneend portion of-the socket member is screw-threaded, as at It), and' the sameend'portionhasa-reduced cylindrical guiding and assembling stem or s-tud' I I The end portion l2 of-the socket-memberconstitutes one of the con:- pling elements and has; circumferentially spaced; equidistant; semispherical; ball seats- [3.

Another important part of the; chuckisthe casing member 14' whichis of cylindrical or s1eevelike form andhasaskirt portion i5 which, is internally screw-threaded and screwed to; thethreads Hi. This provides an adjusting and hous ing unit for the coiled tensioningspring l6, s,aid;

spring being in the spring chamber IT; The outer The next and' asignificant part ofthe, chuck, is:

the't'aper-shan'k member or unit 19; This has acylindrical portion 20 which projects through an opening in the casing I 4 and which terminates in a flange 2! which is opposed in parallelism to the surface [2 whereby to form the othercoupling element. This flange has semi-spherical recesses 22 providing additional seats for the coacting half-portions of the jointing or coupling balls 23. To add to the stability, the cylindrical portion 20 has an axial socket 24 for telescopic and rotatable reception of the coacting stem I l. Thus, We have a socket member 8 provided with a socket 1 on one end and a reduced axial stem II on the 0pposite end, said stem extending into a socket 24 to axially join the two main members 20 and 8 in driving relationship. Novelty is predicated, however, upon a simple casing 14 adjustably threaded on the socket member '8 to tension the spring [6 which is housed in the chamber 11 of the casing and to enable the simple flange 2! and surface l2 to come together in coupling relationship and to accommodate the overrunning coupling balls 23. Normally, the shank l 9 and socket member 8 are coupled and turned together, whereby to provide a driving structure for the driven tap 5. In case an excessive overload is encountered while the tap is being driven from a suitable source of power, by way of my improved chuck, the latter automatically provides the safety cut-out achievement. That is to say, the cou- 3 pling functions as a well known type of overrunning clutch, and disruptable damage to the parts is thus overcome.

I am not unmindful that overrunning clutches have been used in so-called torsional wrenches. I know of none which, however, include the specific details 8, II, I4, coupling members l2 and 2|, with 2| constituting a spring-pressed flange Whose pressure may be regulated in the manner evident from my drawings.

In actual practice, the upper end portion of casing member I4 is provided, if desired, with diametrically opposite flat surfaces 24-24 which constitute wrench-grips. Also, and here again it is optional, the socket member is provided with diametrically opposite fiat faces 25-25 which serve as additional wrench grips. This makes it possible to place a wrench securely on the parts 8 and I4, respectively, to hold them for purposes of adjusting same and regulating the tension of the spring l6. If preferred and instead of using wrench grips 24 and 25, the parts I4 and 8 may be provided in diametrically opposite sides with holes 26 and 2?, respectively, to accommodate an insertable and removable rod which may be used as a turning handle (not shown). This makes it possible to provide parts 8 and M with surfaces 25 and 24 or 21 and 26, whichever is preferred, or both features may be used if such is the decision of the manufacturer.

It is also clear that by changing the setting and size of the balls and the seats in which the balls are fitted, this changes the interference angle and thus effects the beginning of the slip or release action the moment an overload of abnormal force occurs.

In view of the foregoing description taken in conjunction with the accompanying drawings, it is believed that a clear understanding of the device will be quite apparent to those skilled in this art. A more detailed description is accordingly deemed unnecessary.

It is to be understood, however, that even though there is herein shown and described a.

preferred embodiment of the invention, the same is susceptible to certain changes fully compreaszsym I 4 hended by the spirit of the invention as herein described and within the scope of the appended claim.

Having described the invention, what is claimed as new is:

A tap holding and rotating chuck of the class shown and described comprising a socket member having an axial socket for removable reception of the shank portion of a tap, said socket member being axially reduced at one end and provided with a cylindrical axial stem, the portion surrounding said stem providing a torque responsive friction coupling element, the latter being provided with circumferentially arranged ball seats, a taper-shank having an axial socket at one end, said stem extending telescopically and rotatably into said socket and further having, at the same end, a flange of a diameter corresponding to the diameter of the socket member, said flange providing a second torque responsive friction coupling element and one surface of the latter having circumferentially spaced ball seats, coupling balls interposed between said coupling elements and fitting into the respective seats provided therein, a coiled spring surrounding the flanged end of said taper shank, and a casing enclosing said spring, said socket member being provided with external screw-threads, said casing having internal screw-threads screwed upon the first-named screw-threads to permit the tension of said spring to be regulated and to thus control the setting of the safety phase of the coupling.

' RAYMOND J. MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS -,Daum Aug. 3, 1943 

